Telecommunications networks typically include components such as ATM switches, frame relay switches, voice switches, routers, servers, and other equipment for processing and transmitting data. These components can be referred to collectively as network elements. Errors, alarms, and other undesirable conditions can occur in network elements. Examples include line bouncing, slow response, and customer reported conditions. Conditions such as these can be referred to as events. In a typical embodiment of a telecommunications network, each network element has a network manager and/or interface to provide fault and performance information on the circuits traversing the network. Notification that an alarm or other event has occurred is typically transmitted to a fault management module where information about an event, such as the type of event and the equipment on which the event occurred, can be read by a technician. The technician then manually searches an event correlation database to determine if the event is ongoing or if it is a new occurrence. For new events, the technician searches a database of network elements to correlate network element identification data received from the fault management module with the name and location of the faulty network element. The technician then performs a series of manual tests on the network element that generated the event notification. If the tests indicate that a fault exists, the technician opens a trouble ticket describing the problem and sends the ticket to the appropriate agency for repair of the problem. The technician manually logs all actions taken in response to the event notification in the trouble ticket.
Many alarms and other events are anomalous, one-time events that do not necessarily indicate an error. Technicians must investigate every event and complete the process described above to verify that an actual error exists. This process is time-consuming, labor-intensive, and expensive.
Two types of testing are typically done on a telecommunications network: physical layer testing and logical layer testing. Testing the physical layer of a network involves investigating the performance of the lowest protocol layers of transport (layer one of the OSI Model), such as Sonet, DS-1, DS-3, etc. Logical layer testing involves verifying the integrity of the performance of the higher protocol layers (layer two and up of the OSI Model), such as ATM, Frame Relay, IP, voice, etc.
Tests that interrupt customer traffic are considered intrusive. They include inserting a test set into a circuit in a manner that causes customer traffic to be interrupted and insertion of test patterns or test traffic to evaluate circuit performance. Tests that do not interrupt customer traffic are considered non-intrusive. They include monitoring circuit performance, monitoring alarm and fault status, verifying mapping and configuration data, and verifying the state of network equipment.